Khiagda, Chita, Russia:

A. G. Ivanov, Deputy Director of Production in Repair and Maintenance, Candidate of Engineering Sciences, Ivanov.a.g@hiagda.ru

“Atomredmetzoloto” JSC, Moscow, Russia:
I. N. Solodov, Director of Innovation and Technological Development Programs, Doctor of Geologo-Mineralogical Sciences

Injection wells for in-situ leaching with acid solutions are the main equipment in the process chain of underground uranium leaching. Their reliable and trouble-free operation over the whole period of life is the top-priority objective. One of the structural elements of such wells is production casing. Preservation of sealing and geometry of the casing during the service life of wells is the critical indication of reliability of the selected injection well design. In turn, these characteristics are in many ways governed by the material of casing pipes. The authors highlight the urgency of accident reduction in construction and operation of injection wells during in-situ leaching. Recently in Russian mines, unplasticized polyvinylchloride casing is widely used in polyethylene tubes. If necessary, PVC pipes can be fitted with modifi ers for application under specific geological conditions. The current experience of operation of PVC casing pipes shows that the adherence to recommendations given in this article allows considerable reduction in accident rate during construction and operation of injection wells. Two out of 51 wells were unaccepted due to PVC casing damage (in both cases, damage was caused by elevation of cement solution above the permafrost floor). Among accepted 49 process wells, no integrity violation was detected in the casing. Put it otherwise, the accident rate index was less than 4%. In wells equipped with low-density polyethylene casing, the accident rate reaches 15%.

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